John Gills Exposition of the Bible Commentary

Verse 21 (Hebrews 10:21)

And having an high priest over the house of God. The church of God, over which Christ is as prophet, priest, and King, and as the Son and owner of it; See Gill on Hebrews 3:6 ; See Gill on Hebrews 4:14 . In the Greek text it is, "a great priest"; so the Messiah is called by the Targum on Zechariah 6:12 כהן רב , "a great priest", as he is; even a great high priest, as in Hebrews 4:14 , and greater than Aaron, and any of his sons.

- John Gills Exposition of the Bible Commentary